Elusive Solution
The Problem:
One or more unrelated applications will not start for the same reason.
The Error Message:
C:\Program Files\Some Application Name\ProblemApp.exe
This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem.
Verify The Problem:
If you are getting this error and reinstallation did not help (it never will in this case), do this: Log on with Administrator rights. Open the event viewer (Control Panel > Administrative Tools) and look at the system log. Find the errors that occurred when you tried to start the application that failed to start. The error source will be listed as Side by Side. See if any of the errors indicate a problem with Microsoft.VC80.CRT or Microsoft.VC80.MFC, or maybe something like that with 'Debug' inserted; plus an indication that the assembly is not installed.
The Solution:
If the above describes your problem, download the Visual C++ 2005 Redistributable SP1 (x86) and install it:
If the link is broken, search microsoft.com for the download title mentioned above. Hopefully this will solve your problem. It worked for me, so good luck.
Why did this happen?
I don't know. My theory: Every application written with Visual C++ uses a common library of functions installed on your computer with the first installation of any C++ application. For any number of reasons, either this library and/or the registry entries pointing to it can easily get corrupted, but the application's MSI cannot see this and fix it. An arbitrary brute force installation of the whole library over the old installation renews the correct relationships.
Why is this here?
Finding a solution to this error was extremely difficult for me, so I posted it here hoping it might help someone. I did not know of a more visible place to post this since it can happen to any application that was developed with Visual C++. Thus, most of the Google hits related to programmers with custom applications and were not of a language of normal people. I'm hoping it will show up in a Google search high enough to help someone else. If you maintain a website, you can help achieve this by linking to this page, especially if you use the error message text as your link text.